Doubles wing

[Spg01]

Hello Tobin,

I have searched around about wing size and found something you wrote that seems to fit my situation and just wanted to double check it.

The only difference is my drysuit and undergarments come in at 26 lbs instead of 24 lbs listed below. So I would guess the torus 57 would be to big and the torus 49 would do a good job? And the torus 42 would be to small.


*****Pasted from different thread*****


Doubles rig

SS plate and harness -6
Dual regs -5
Bands and manifold -5
2 x hp 100 full of air or nitrox -21
Can light -2

Total with full tanks -39
Total with empty tanks -23

You need to start the dive negative by the weight of your Backgas 2 x 100 = ~16 lbs of air or nitrox.

You should add another 2-3 lbs to allow for extra suit inflation, no shrink wrap at your shallow stop

That means to stay at the surface at the beginning of the dive with full tanks you will use about 16 + 3 = 19 lbs of the capacity of your wing.

You need in reserve enough capacity to deal with a total failure of your suit.

19 + 24 = 43 lbs.

Your rig will provide about 23 lbs of ballast with empty bottles, and you need 27. (24 lbs of suit buoyancy +3 for extra inflation)

If you add 4 lbs of ballast to your rig, for example a couple soft weight pouches between the wing and back plate, your rig will now be 43 lbs negative at the start of the dive.

Bingo! Suit + gas + 3 = 43 and your rig is 43 lbs negative.

You need a wing that's larger than 43 lbs. Something in the 49 -50 lb range is reasonable.

 

[cool_hardware52]

Hello Tobin,

I have searched around about wing size and found something you wrote that seems to fit my situation and just wanted to double check it.

The only difference is my drysuit and undergarments come in at 26 lbs instead of 24 lbs listed below. So I would guess the torus 57 would be to big and the torus 49 would do a good job? And the torus 42 would be to small.


*****Pasted from different thread*****


Doubles rig

SS plate and harness -6
Dual regs -5
Bands and manifold -5
2 x hp 100 full of air or nitrox -21
Can light -2

Total with full tanks -39
Total with empty tanks -23

You need to start the dive negative by the weight of your Backgas 2 x 100 = ~16 lbs of air or nitrox.

You should add another 2-3 lbs to allow for extra suit inflation, no shrink wrap at your shallow stop

That means to stay at the surface at the beginning of the dive with full tanks you will use about 16 + 3 = 19 lbs of the capacity of your wing.

You need in reserve enough capacity to deal with a total failure of your suit.

19 + 24 = 43 lbs.

Your rig will provide about 23 lbs of ballast with empty bottles, and you need 27. (24 lbs of suit buoyancy +3 for extra inflation)

If you add 4 lbs of ballast to your rig, for example a couple soft weight pouches between the wing and back plate, your rig will now be 43 lbs negative at the start of the dive.

Bingo! Suit + gas + 3 = 43 and your rig is 43 lbs negative.

You need a wing that's larger than 43 lbs. Something in the 49 -50 lb range is reasonable.

If you are using 2 X 100's and a suit that's is 26 lbs positive, then you need a wing that is 16 + 26 + 3 = 45 lbs. A 49 is a reasonable choice.

Tobin

 

[Spg01]

Thanks for the reply.

Would the 57 be a bad choice?

 

[cool_hardware52]

Thanks for the reply.

Would the 57 be a bad choice?

You don't need a 57. Too much wing is not "free" It will be less stable, and make venting more difficult vs a properly sized wing.

Tobin

 

[Spg01]

thanks for the good info Tobin. I will hopefully order the 49 this weekend.

 

[elan]

I have a suit that is as buoyant as yours, and I dived Worthingtons HP100 with 49lb. It worked well buoyancy wise. I still dive the same T49.
If your tanks are Worthingtons HP100 then the issue that you will have (and this is not the wing problem) the HP100 being short will always try to "step" on the bottom of the wing when you place the tanks on the bench. Those tanks are short and the wing tends to fold under the tanks, so if you have something sticking out from a bench - theoretically you can damage it.

I sold the HP100s because they were short for me. With FB LP85, AL80 and LP108 (slightly under filled) the wing works well. HP130s or overfilled LP108 will sink it.